System and method for security inspection using microwave imaging

Abstract

A microwave imaging system uses microwave radiation provided by a microwave source to image targets. The system includes an array of antenna elements that are capable of being programmed with a respective direction coefficient to direct the microwave illumination from the microwave source toward a position on the target. The antenna elements are further capable of being programmed to receive reflected microwave illumination reflected from the position on the target. A processor is operable to measure an intensity of the reflected microwave illumination to determine a value of a pixel within an image of the target. Multiple beams can be directed towards the target to obtain corresponding pixel values for use by the processor in constructing the image.

Description

BENEFIT CLAIM UNDER 35 U.S.C. § 120 [0001] This application is a continuation of U.S. Non-provisional Application for patent Ser. No. 10 / 996,764 filed on Nov. 24, 2004. CROSS-REFERENCE TO RELATED APPLICATIONS [0002] This application is related by subject matter to U.S. Non-provisional Application for patent Ser. No. ______ (Attorney Docket No. 10040151), entitled “A Device for Reflecting Electromagnetic Radiation” and U.S. Non-provisional Application for patent Ser. No. ______ (Attorney Docket No. 10040580), entitled “Broadband Binary Phased Antenna,” both of which were filed on Nov. 24, 2004.BACKGROUND OF THE INVENTION [0003] In response to an increasing threat of terrorism, inspection of persons and other items for weapons and other types of contraband is becoming essential at security checkpoints, such as those found at airports, concerts, sporting events, courtrooms, federal buildings, schools and other types of public and private facilities potentially at risk from terrorist at...

AI Technical Summary

Benefits of technology

The present invention provides a microwave imaging system that uses microwave radiation to image targets. The system includes a microwave source and an array of antenna elements that can be programmed to direct the microwave illumination and receive reflected microwave illumination from the target. The intensity of the reflected microwave illumination is measured to determine the value of a pixel in the image of the target. Multiple beams can be directed towards the target to obtain corresponding pixel values for use by the processor in constructing the image. The technical effect of this invention is to provide a non-invasive and non-contact microwave imaging system that can provide high-quality images of targets with improved accuracy and resolution.

Problems solved by technology

However, physical inspection by security personnel is tedious, unreliable and invasive.

In addition, metal detectors are prone to false alarms, and are not capable of detecting non-metallic objects, such as plastic or liquid explosives, plastic or ceramic handguns or knives and drugs.

Furthermore, X-ray systems pose a health risk, particularly to those people who are repeatedly exposed to X-ray radiation, such as airport personnel, and X-ray systems also are not able detect certain materials / geometries, such as ceramic knives.

However, such scanning systems typically require mechanically moving parts and / or intensive post-processing reconstruction of the image, both of which increase the cost and complexity of the microwave imaging system.

However, microwave imaging systems that use lenses to focus the microwave energy typically have a limited field of view and small aperture size.

In addition, the cost of the lens system may be prohibitively large in many applications.

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